Attention has been focused on the automatic operation technology for automatic steering of vehicles. For example, disclosed is a technique for providing assistance to traveling based on information of an environment around vehicles.
For example, disclosed in JP-A 2007-257519 (KOKAI) is the technique for predicting an avoidance line for preventing a collision on the basis of a result of prediction of the travel line of another vehicle.
Here, the degradation status of a road surface influences a travel environment. For example, a tire of a vehicle caught in a rut would cause the vehicle to travel with difficulty. However, the degradation status of a road surface has never been taken into account. Thus, travel assistance that depends on the road surface status has not been provided.